The present invention relates to a vehicular alternating current (AC) dynamo which can prevent vibration of brush and an excessive rise in its temperature.
As disclosed in JP, A, 62-144551, for example, the conventional protective structure for a brush surrounding region of a vehicular AC dynamo is arranged as follows. A fan guide is provided to serve as a member for introducing air induced by a cooling fan fixed to a rotor coil. This fan guide and a tubular cover surrounding a slip ring are integrally molded using a resin. The tubular cover is provided with a cutout having two parallel edges extended parallel to a rotary shaft. These two parallel edges and engagement portions (recesses) formed in the side of a brush holder are engaged with each other, thereby improving a sealing ability for a portion of the slip ring which is held in slide contact with a brush.